Shock Wave Interaction with Matter

Abstract

The interaction of shock waves with concretions inside the human body is a vast research field and although considerable progress has been made to understand the phenomena involved, there are still questions to be answered. Even more complicated are the physical and biochemical mechanisms involved in tissue damage. In many situations, secondary effects of shock wave passage are more important than the direct influence of the shock wave itself. Spallation, cavitation, circumferential compression, stress, fatigue, and other calculi fragmentation mechanisms are explained in this chapter. Some experimental shock wave sources designed to enhance stone fragmentation and reduce tissue damage during extracorporeal lithotripsy are shown as examples of the worldwide efforts to improve clinical equipment. The final section of this chapter deals with the effects produced on the human body during extracorporeal shock wave therapy. Main subjects include the translation of mechanical stimuli into biochemical signals, stimulation of the cells responsible for bone healing, tissue, nerve and axonal regeneration, activation of pain control systems, reduction of oxidative stress and inflammation, enhancement of endothelial capillary connections, collagen matrix changes, and differentiation of stem cells. Other topics involving shock wave interaction with cells, such as gene transfection, genetic transformation of microorganisms, and the bactericidal effect of shock waves, are discussed in Chap. 7.